Which is present in very little quantity in the body ?

Options

A. K
B. Ca
C. Mg
D. Cu.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which element is present in very little quantity in the body among the given options: potassium (K), calcium (Ca), magnesium (Mg), and copper (Cu).

2. **Analyzing Each Option**:
- **Potassium (K)**: Potassium is an essential mineral that plays a crucial role in nerve transmission and maintaining the potential gradient in body fluids. It is present in significant amounts in the body.
- **Calcium (Ca)**: Calcium is vital for various bodily functions, including bone health and muscle contraction. It is also abundant in the body.
- **Magnesium (Mg)**: Magnesium acts as a cofactor for many metabolic reactions, including glycolysis. It is present in moderate amounts in the body.
- **Copper (Cu)**: Copper is an essential trace element, meaning it is required in very small amounts. It is involved in the formation of transport proteins and is the least abundant of the four elements listed.

3. **Conclusion**: After analyzing the roles and abundance of each element in the body, it is clear that copper is present in very little quantity compared to potassium, calcium, and magnesium.

4. **Final Answer**: The correct option is **copper (Cu)**.